I got a code 27 (metering pump). I was told its the pump or the wiring. Just tested both wiring and the pump just like the FSM tells me to do. I'm very glad that it was NOT my wiring harness (too expensive and a PITA to replace). Now the FSM tells me to test the OMP and that it should have 14-36ohms resistance between 4 pins and between other 4 pins should have OPEN connection. My OMP does indeed have the 26ohms on the 4 pins like it should, but the other 4 pins where it should be OPEN I get no connection. Can anyone confirm to me that this for sure means my OMP is bad before I spend a bunch of money and time replacing it?

Any comments, suggestions more then welcome. Thanks everyone

 

Either condition A or condition B is to be is to be satisfied but not both at the same time when measuring the MOP connector. So, if one of the conditions are good you should be OK.

Second, did you verify 12 VDC at B1 and B2 on the harness when the key on?

Third, did you verify voltage at the PCM connector (4I, 4J, 4K, and 4L) for the stepper motor?

Last, did you verify position voltage at the PCM per the FSM?

 

First off YES b1 b2 have voltage in on position

tested the wiring from the ecu 4 IJKL all have good connection so its not the wiring

My problem is that when I test the motor OMP like FSM say I do get the resistance like it says I should (I think mine is A) resistance falls with in the allowed 16-34ohms (mine at 26ohms) but the FSM also says you should get OPEN connection between the other pins & and my OMP shows NO connection there. Just want someone who has tested these before to confirm to me that if I don't get OPEN connection that it is indeed a bad OMP.

Thanks a ton guys

 

By "open" if you mean no continuity and the FSM says for those pins no continuity to B1 or B2 the MOP should be good; at least as far as the FSM goes.

There is another test you can do if you do not have a PFC and that is to monitor the position sensor feed back voltage at the PCM during driving. If it varies and voltage increases as engine rpm and load increases the MOP stepper motor is working.

If the MOP is failed it does not mean that your engine is not getting oil injected it is simply getting the metered amount for idle and low rpm driving.

Question - sometimes rarely the PCM will set an error on an unexpected measurement based upon where it has set the stepper motor set. Have you pulled off the battery cable to dump the PCM and monitored if the code is set again? This may be just one of those things.

 

I got the same code a few years ago. IIRC, I did all the continuity and resistance checks I could do at the connector behind the alternator and everything was within spec just as you found....yet I had the code. I proceeded with the OMP replacement and that cured the issue.

And FWIW, I think that the stepper motor works on a 1 to 5v range and if it fails, it defaults at 5v. I interpreted that to mean it was injecting max amount but not sure.

If you end up replacing the OMP, search for threads under my name for one person's how-to.

 

See this other thread for some history on his problem:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/premix-apexi-power-fc-2-eliminate-oil-injection-893000/

 

Hey when you replaced your OMP did you have the stock twins on there? And did they get in the way of removing the OMP? I hope I don't have to mess with them to get the new OMP in and old one out.

 

Yea gracer7 that's also my thread. I know I'm gonna get an apexi power fc so I was just contemplating doing it now and not having to fix the OMP, or fix the OMP and wait on the power fc

 

Yes.

 

Just an update, I tested the omp pump, omp sensor and wiring. Everything is as it should be until I test the V0 wire from the OMP sensor. It should have 1.1v at idle (it does) and it should increase the voltage as the engine speeds up (im guessing just high RPM should do it) but mine does not. It always stays at 1.1v regardless of what RPM I have the engine at.

Does anyone know it this should be tested under load on the motor maybe? Or maybe under boost? All I've tried is testing it with higher RPMs and the sensor keeps showing 1.14v all the time so I'm guessing this is what is giving me the LIMP mode and code 27.

 

I'm also getting a similar reading except mine is at 1.07 and doesn't seem to move. Is the voltage increase tied to load or just rpm?

 

I believe the FD OMP output is based on both. The stepper motor position is dependent on the 1 to 5v input and voltage is determined by the ECU based on load and rpm.

If your interested, ttmott (who posted earlier in this thread) put up a few informative posts on the OMP........
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/omp-declassified-892750/
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/omp-declassified-part-ii-895388/

 

Thanks,

I just read through all of that, now I know which parameters equal what in the PFC. You guys rock!